1. Field of the Invention
The present invention relates to a charging circuit for an electronic device and a related charging method, and more particularly, to a charging circuit and a related charging method capable of performing different types of charging.
2. Description of the Prior Art
With rapid economic development in the world, living standard of people increases continuously. There are more and more portable electronic products emerging, such as laptop, tablet, mobile phone, digital camera, portable DVD player, personal digital assistant (PDA), MP3 player and global positioning system (GPS). Since these devices have to support long time usage, charging functions are required for batteries of these devices.
The selection of adaptors for modern portable electronic products has to be determined in consideration of both industrial design and charging circuit design. However, most of the charging circuits of available portable electronic products can only support buck charging. Once the selection of adaptors is limited such that feasible adaptors cannot be compatible with buck charging due to industrial design or other reasons, additional boost circuits should be applied to satisfy charging requirements. For example, sometimes there are only universal serial bus (USB) ports left by the manufacturer, and the USB ports can only provide 5V power. As a result, when the battery voltage of the portable electronic product is higher than 5V, the USB ports may not perform charging on the battery, and additional boost circuits must be required, which increases costs and circuit complexity.
Besides, in order to satisfy various applications of portable products, the battery has to support various types of adaptors, such that circuit areas maybe increased, printed circuit board (PCB) space may be reduced, and costs of design may also be increased, which further increases the difficulty of design.